Vacuum drying apparatus



H. D. MILES Nov. 10 l925- VACUUM DRYING APPARATUS 3 Sheets-Sheet 1 .//z%rizeys Filed Dec. 31, 192

H. D. MILES VACUUM DRYING APPARATUS Filed Dec. 51, 1924 s Sheets-sheaf 2 71 van r Nov. 10, 1925 1,560,598

H. D. MILES VACUUM DRYING APPARATUS Filed Dec. 31, 1924 3 Sheets-Sheet I5 a m H o O 0 o Jar/621%? My 4). (may 2y 6? W Patented Nov. 10, 1925.

UNITED STATES PATENT OFFICE.

HENRY D MILES, O'F BUFFALO, NEW YORK, ASSIGNOR TO BUFFALO FOUNDRY 85 HA.-

OHINE COMPANY, OF BUFFALO, NEW YORK, A. CORPORATION OF NEW YORK.

vAcoUm nnvme ArrAnA'rUs.

Application filed December 31, 1924. Serial No. 759,203.

To all whom it may concern: A

Be it known that I, HENRY D. MILES, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented new and useful Improvements in Vacuum Drying Apparatus, of which the following is a specification.

This invention relates to a vacuum drying apparatus, and more particularly to an apparatus of the character which permits of recovering the valuable dust constituents contained in vapor which is withdrawn from the liquid being desiccated and saving the same. 1

In vacuum drying apparatus, as heretofore constructed, the vapor withdrawn from the drying chamber was passed through water in a dust collector whereby the dust was absorbed by the water and eventually wasted when the water was discharged from the collector at the end of each day.

It is the object of this invention to provide a vacuum drying apparatus which is combined with a dust collector in such manner that the vapors and dust withdrawn from the drying chamber while 'desiccating under vacuo are passed through the liquid intended to be supplied to the means which feed the sameto the drying drum, thereby extracting the dust from the vapors and effecting a substantial saving of desiccated material which otherwise would be lost.

In the accompanying drawings z Figure 1, is a side elevation of a vacuum apparatus embodying my invention.

Figure 2, is a vertical longitudinal section of the same.

Figure 3, is a vertical transverse section of the apparatus taken on line 3-,3, Figure 2.

Similar characters of reference indicate like parts throughout the several views.

The numeral 10 represents the drying chamber of the apparatuswhich is formed within an enclosing casing 11 and in which a vacuum is formed by withdrawing the free or floating contents of the drying chamber through a vapor and dust outlet 12 in the upper part thereof.

Mounted within the drying chamber so as to rotate about a horizontalaxi's isa 'hori-. zontal drying drum 13 which is heated internally by supplying a heating medium thereto, such as steam. By this means a heated peripheral surface is produced on the drum whereby any solids containing liquid deposited on'the drum will be desiccated, this process being accelerated and accomplished at a low temperature due to the vacuum in said chamber.

The liquid to be desiccated is presented to the underside of the drum by a feeding pan 14 so that the drum as it rotates dips with its underside into the liquid within the pan and picks up a thin film of the same. This film is spread uniformly over the surface of the drum by a spreader 15 and as the film of liquid is carried upwardly on one side of the drum and downwardly on the other side of.

the same it is deprived of its moisture and then removed from the drum preparatory to depositing a fresh film thereon. The re moval of the dried film from the drum is effected by a knife or scraper 16 from which the dried material is directed into a conveyor trough 17 and carried away by a conveyor or, screw 18.

The excess liquid which escapes from the feeding pan overflows the edge of the same and drops into an overflow trough 19 which is arranged in the drying chamber below the feeding pan so as to catch said excess liquid.

The apparatus for dr ing the liquid is combined with means or supplying the liquid to be dried, circulating the excess the following means are provided 2-- liquid, exhausting the vapor and dust from The numeral 20 represents an upright dust collecting chamber. which is adapted to contain a body of the liquid in its lower part while the upper part of the space therein is free. Below the normal liquid level of-the chamber the same is provided with a liquid inlet 21 through which the liquid to be desiccated may be supplied from any-suitable source-and the. supply regulated in any approved manner.

The liquid is withdrawn from this 'dust collecting chamber through a liquid outlet 22 in its bottom or lower part which is connected by a pipe 23 with the inlet of a pump 24. From the outlet of the latterthe liquid is delivered by a pipe 25 to the feeding pan for replenishing the same with liquid and keeping the same supplied with a stream of liquid in excess of the picking up capacity of the drum so that some of the liquid will overflow from the pan and drop into the in this trough is returned from the same to the liquid in the dust collecting chamber by a return pipe 26 connected at one end with the overflow trough and opening at its op osite end into the dust collecting 1 chamber below the normal liquid level therein, whereby this liquid is again put in circulation and fed with the other liquid in the dust collecting chamber to the drying drum.

The vapors and dust withdrawn from the drying chamber are carried through a pipe or conduit 27 which connects at one end with the vapor and dust outlet 12 of the drying chamber while its other end extends into the dust collecting chamber and terminates in the liquid below the normal level of the same.

In its upper part or top the dust e01- lecting chamber has a vapor outlet28 which is connected by a conduit or pipe 29 with an exhausting device of any suitable character, such-as a pump or condenser, for withdrawing the dust and vapors from the drying chamber and creating a vacuum therein. I

As the dust and vapors are withdrawn from the drying chamber the same are de-' livered by the pipe 27 into the liquid in the collecting chamber below the level of the same. These vapors pass in the form of bubbles upwardly through the liquid in the collecting chamber and any dust entrained therein is absorbed by the liquid and carried away with the latter by the pump and .again presented by the feeding pan to the drying drum. The vapors which rise to the top of the liquid in the collecting chamber are now no longer dust laden inasmuch as the dust has been washed out of the same by the liquid and this liberated vapor is now carried oil through the vapor outlet of the collecting chamber by the exhausting device connected therewith, thereby maintaining a vacuum in the drying chamber.

By thus utilizing the liquld supply of the apparatus as means for absorbing the dust which has been drawn'with the vapors from the drying apparatus by vacuum this dust is recovered and added to thisoutput of the machine and effecting a sub- 'stantial saving, particularly in the case of valuable material such as powdered milk and the like.

vapor and dust, a drying overflow trough. The excess liquid caught I claim asmy invention 1. A vacuum drying apparatus comprising means for desiccatin the liquid, means for supplying the liqui to be desiccated, and means for producing a vacuum in the apparatus having a conduit leading from said desiccating means into said liquid supplyin means.

2. vacuum drying apparatus comprising a drying chamber havin an outlet for rum movably arranged in the drying chamber, feedin means for-supplying the liquid to be dried to said drum, a dust collecting chamber adapted to contain liquid to be desiccated and provided with a hquid. supply, a vapor outlet in its upper art adapted to be connected with an e austing device, and a liquid outlet in its lower part, a pump for withdrawing the li uid from said dust collectin chamber an delivering the same to said eeding means, and a vapor and dust conduit connected at one end with the vapor vand dust outlet of said drying chamber and having its opposite end terminating in said dust collecting chamber below the liquid level therein.

3. A vacuum drying apparatus comprising a drying chamber having an outlet for vapor and dust, a rotary drying drum arranged within said chamber, feeding means for supplying the liquid to be desiccated to said drum, an overflow trough adapted to catch the excess liquid escaping from said feeding means, a dust collecting chamber adapted to contain li uid to be desiccated and provided in its si e with a liquid sup: ply, in its top with an outlet adapted to be connected with an exhausting device and in its bottom with a liquid outlet, a vapor pipe having its inlet connected with the outlet of said drying chamber and its outlet extending into said dust collecting cham her and terminating belowthe level of the liquid therein, a liquid return pipe exten'ding from said overflow trough into said dust collecting chamber and terminating below the liquid level therein, and a liquid circulating pump having an inlet connected with the liquid outlet of said dust collecting chamber and also having an outlet which is connected with said liquid feeding means.

4. The hereindescribed method of desiccatin liquid which consists in feeding the liqui to be desiccated to a moving heated surface which is in vacuo, maintaining a supply of 1i uid from whichthe' same is drawn and eli v er ed-to the means which feedthe-sanie to" said moving heated surface, and conducting the. vapors and dust 115 withdrawn by vacuo from liquid while being desiccated on said moving surface and delivering the same into said supply of liquid.

5. The hereindescribed' method of .desiccatin liquid which consists in feeding the drawn b vacuo from liquid while being liqui to be desiccated to a moving heated desiccated on said movin surface and desurface which is in vacuo, maintaining a livering the same into sai supply of liquid 10 supply of liquid from which the same is and catching the excess liquid which escapes 5 drawn and elivered to the means which during said feeding o ration and returnfeed the same to said moving heated suring the same to said i uid sup 1 face, conducting the vapors and dust with- HElgRY D. 

